The involvement of calcium mobilization in the calcium-activated potassium currents activated by hyposmotic swelling in gastric antral circular myocytes of the guinea-pig

In our study of the effects of hyposmotic swelling on the Ca(2+)-activated potassium currents [I(K(Ca))] and its mechanism, we employed the whole-cell patch clamp technique using the gastric antral circular myocytes of the guinea-pig. Hyposmotic swelling efficiently increased I(K(Ca)), and the extent of changes in I(K(Ca)) was sharply dependent on the osmolarity of the perfusion solutions. When the calcium-free solution (EGTA 10 microM added in calcium-free solution) was superfused, I(K(Ca)) was not increased by the hyposmotic swelling. Gadolinium (Gd(3+)) 100 nM, a blocker of the stretch-activated nonselective cation channel, blocked the activation of I(K(Ca)) induced by hyposmotic swelling, but nicardipine 5 microM (the L-type calcium channel blocker) did not. Heparin 3 mg/ml, a potent inhibitor of inositol triphosphate receptor (InsP(3)R), did not inhibit the response, and caffeine 1 mM (the agonist for calcium-induced calcium release [CICR]) imitated the effect of hyposmotic swelling. Ryanodine (15 microM), markedly inhibited the effect. These results suggest that hyposmotic swelling activates I(K(Ca)), and the activation is associated with CICR, which is triggered by extracellular calcium influx through the stretch-activated channel (SA channel).     

Activated CD8(+) T cells from aged mice exhibit decreased activation-induced cell death

To uncouple the defects of activation and apoptosis of T cells from aged mice, we used anti-CD3 plus IL-2 stimulation to induce an activation response and analyzed the subsequent activation-induced cell death (AICD) response of T cells from 16-month-old mice. The results herein demonstrate that T cells from 16-month-old mice could be activated by anti-CD3-induced activation signals but exhibited distinct phenotypic and functional features compared to young (2-month-old) mice. These include a decrease in AICD, a delayed entry into the cell cycle, and a decreased telomerase activity. The decreased AICD of T cells from 16-month-old mice is associated with a decreased expression of Fas and Fas ligand (FasL), decreased susceptibility to anti-Fas-induced apoptosis, and an increased expansion of a CD8(+) T-cell population. Prior to activation, these T cells exhibit a phenotype that is CD44(hi)CD62L(hi). After stimulation, these T cells produced high levels of the pro-inflammatory cytokine, IFN-gamma, and developed an increased population of IFN-gamma(+)IFN-gamma R(-) T cells. Our results suggest that there is a dysregulation in T-cell homeostasis in aged mice associated with a decrease in AICD of CD8(+) T cells.     

Quercetin inhibits the invasion and mobility of murine melanoma B16-BL6 cells through inducing apoptosis via decreasing Bcl-2 expression

Quercetin has been known to have anti-tumor and anti-oxidation activities. In the present study, we have investigated its in vitro anti-metastatic activity. Quercetin inhibited the invasion and mobility of murine melanoma B16-BL6 cells in a dose-dependent manner but did not affect their adhesion to either laminin, fibronectin, or type VI collagen. Moreover, quercetin significantly inhibited the proliferation of B16-BL6 cells only in the case of time incubation longer than 48 h. Quercetin dose-dependently decreased the cell rates in S and G2–M phases of cell cycle. The effect of quercetin to cause a remarkable apoptosis of B16-BL6 cells was also demonstrated by flow cytometric assay as well as DNA fragmentation with a typical 180-bp ladder band in agarose electrophoresis and a quantitative analysis. Furthermore, quercetin markedly inhibited the expression of anti-apoptotic protein Bcl-2 but hardly influenced Bcl-X_L. These results suggest that the inhibition of quercetin on invasiveness and migration of B16-BL6 cells are closely associated with the arrest of cell cycle as well as the induction of apoptosis by decreasing the Bcl-2 expression. This revised version was published online in July 2006 with corrections to the Cover Date.     

海洛因依赖患者的MMPI与ERP电位研究

目的:探讨明尼苏达多项人格调查量表(MMPI)及事件相关电位(ERP)在海洛因依赖患者中的临床应用价值。方法:对44例海洛因依赖患者和43例正常健康者分别进行了MMPI及ERP测定,并将两组的结果加以比较。结果:海洛因依赖患者中MMPI测定异常率为63.64%(28/44),其量表中Hs(疑病),D(抑郁),Pd(心理变态)、Pa(偏执)、Pt(精神衰弱),Ma(轻躁狂)分显著高于对照组(P<0.01)。海洛因依赖患者ERP测定异常率为52.27%(23/44),其中N2波及P3波(即P300)潜伏期较对照组明显延长,波幅也降低,两组间比较差异有显著意义(P<0.01)。结论:MMPI及ERP电位对海洛因依赖患者临床诊治及预后判断有较高的价值。     

旋转叶轮血泵的发展与展望

主要从结构设计、轴承密封设计、控制系统设计三个方面介绍了旋转叶轮血泵技术的最新发展 ,并对其发展趋势做出了展望。     

重症肌无力患者外周血B7：CD28／CTLA4共刺激分子表达的动态变化

目的：研究重症肌无力（MG）患者B7：CD28／CTLA4共刺激通路相关分子表达动态变化及其与MG发病的关系。方法：用流式细胞仪检测18例MG患者和16例健康对照者外周血单个核细胞（PBMC）在经PMA（佛波酯）＋ionomycin(钙离子导入剂）刺激的0h,6h,24h,48h时B7－1、B7－2、CD28、CTLA4分子在CD4^ T细胞和CD8^ T细胞表面的表达。结果：（1）0h,MG患者B7－1、B7－2分子总体表达增加，CD4^ 、CD8^ T细胞表面B7－1、B7－2的表达未见明显增加，PMA＋ionomycin刺激后B7－1、B7－2在CD4^ 、CD8^ T细胞表面也无增加；（2）0h,CD28、CTLA4的表达增强，其中CD28^ 细胞的增多主要表现在CD4^ T细胞亚群，CTLA4的表达增强主要在CD8^ T细胞，在PMA＋ionomycin激活后，CD28表达明显增强，持续到48h都处于较高水平（与对照组相比P＜0．01），CTLA4表达出现短暂增强，6h即达高峰，以后下降，与对照组相比无显著增强（P＞0．05）。结论：MG患者外周血中B7：CD28／CTLA4通路共刺激相关分子表达增高，持续时间延长，检测共刺激分子的表达可反映机体的免疫激活状态，B7：CD28／CTLA4通路在MG发病中可能起重要作用。     

用压力容积关系测量颅内顺应性的一种方法

为建立用压力-容积关系测量颅内顺应性的方法,选用12条狗安置硬膜外球囊,通过恒速注液和抽液改变球囊内液量,从而改变颅内容积和颅内压,由压力传感器持续记录脑室内压力,分别用二次抛物线、幂指数、对数关系式对颅腔的P-V实验数据进行拟合,从而求得各关系式的系数.通过对系数的分析研究颅内顺应性.结果表明(1)二次抛物线关系式中的系数满足线性关系;(2)指数关系比抛物线关系拟合得更好,压力较高时更是如此;(3)简化的对数关系式在压力较高时可以近似拟合容积压力关系;(4)在一定范围内,颅内顺应性对应变率不敏感.     

前列腺素E1对大鼠卵泡壁发育和分化影响的形态学观察

本文应用组织学方法和电镜对PGE1引起未成熟大鼠卵泡颗粒细胞和卵泡膜外层细胞的形态学变化作了研究。结果表明:外源性PGE1刺激了颗粒细胞的发育和黄体化,同时也促进了卵泡膜外层细胞的发育和从成纤维细胞向平滑肌细胞分化。文中对有关PGE1在排卵过程中的作用机制等问题进行了讨论。     

HLA-DPA1 promoter haplotypes are differently distributed in southern Chinese ethnic groups

DPA1 gene is one of the human leukocyte antigen (HLA) class II genes and its promoter is highly polymorphic. From comparative studies among five southern Chinese populations, Jing, Li, Bai, Lahu, and Meizhou Han, we describe their single-nucleotide polymorphism (SNP)/haplotype frequency data of HLA-DPA1 gene promoter in this study. Within the 760-bp promoter region, we have identified 21 SNPs and nine possible haplotypes. Pair-wise comparisons show similar frequencies distribution of the HLA-DPA1 promoter haplotypes among Jing, Li, and Bai, whereas all pair-wise comparisons involved with Lahu or Meizhou Han and other ethnic groups show remarkable difference. The differences in frequencies of HLA-DPA1 promoter alleles may reveal different ethnic origins and demographic histories of the five populations. Our study may help distinguishing each of these populations by sequence variations of HLA-DPA1 promoter, which may be served as functional molecular markers for clinical and immunological studies involving the DPA1 locus.